Bucket -> Lambda event deleted when updating prefix

[andrewrch]

I successfully created a bucket with custom name and added an event handler to trigger a lambda

const bucket = new s3.Bucket(this, 'Bucket', {
    bucketName: 'custom-name'
});

bucket.grantRead(lambda.role);
bucket.onEvent(s3.EventType.ObjectCreated, lambda, {
    prefix: 'some-prefix',
    suffix: '.json'
});

This worked fine when deploying initially however when I modified the prefix and redeployed my stack, the event was actually deleted.

Cloudformation events look like this (resource names altered):

17 Jan 2019 11:35:18 | BucketNotifications1529E2E1 | DELETE_COMPLETE                     | -
17 Jan 2019 11:35:15 | BucketNotifications1529E2E1 | DELETE_IN_PROGRESS                  | -
17 Jan 2019 11:35:14 | Stack                       | UPDATE_COMPLETE_CLEANUP_IN_PROGRESS | -
17 Jan 2019 11:35:12 | BucketNotifications1529E2E1 | UPDATE_COMPLETE                     | -
17 Jan 2019 11:35:11 | BucketNotifications1529E2E1 | UPDATE_IN_PROGRESS                  | Requested update required the provider to create a new physical resource
17 Jan 2019 11:35:05 | BucketNotifications1529E2E1 | UPDATE_IN_PROGRESS                  | -

[saksiuchenka]

I experience the same issue and found the root cause at @aws-cdk\aws-s3\lib\notifications-resource\notifications-resource-handler.ts line 138

The problem is CloudFormation sends Delete event right after Update event when PhysicalResourceId changed during Update event. It treats this condition as resource replacement.

I'd propose to change this:
PhysicalResourceId: context.logStreamName,
to that:
PhysicalResourceId: event.PhysicalResourceId || `${event.LogicalResourceId}-${props.BucketName}`,

Can I somehow create a pull request?

[rix0rrr]

Yes you can!

First you fork the CDK repository to your own GitHub account, then you clone it to your disk and follow the CONTRIBUTING guide:

https://github.com/aws/aws-cdk/blob/master/CONTRIBUTING.md

[saksiuchenka]

Thank you Rico,

I just created my PR.